How do I know if my wood front door's finish is weather proof?

Question

We just moved into a new home. The wood front door is semi-sheltered by a small porch. The front of the house has southern exposure and has the most exposure to the weather. There was an unsightly screen door on the outside that we removed.

The door has a semi-glossy varnish-like finish, and I am worried that removing the screen door may expose the door to more moisture. The screen wasn't much protection, but it probably kept rain from blowing against the door.

How do I determine whether the door's finish is appropriate for its exposure to the weather?

Answer 1

All exterior wood finishes that are "suitable for sun exposure" still slowly degrade in the sun (it's worse than water, actually) and need to be renewed - Just ask the folks with wooden boats. So whether or not the current finish is "weather resistant" (since "weather proof" is not really accurate) it will need to be renewed.

The simplest approach is to re-coat it now with spar varnish or some other exterior clear finish (spar urethane would be the other common one) and then you know what it's got on there. Then plan to re-coat before significant damage accrues - it's easier to maintain a finish than to try and restore the look of wood that has been damaged or discolored by weathering.

Answer 2

UV light is actually probably a bigger concern than water. All but the most delicate finishes will provide decent water resistance, but UV light will break down anything not specifically designed for it.

An exterior door should be finished with something outdoor-rated, like spar varnish. I'm not sure there's any way for you to tell by looking at it, but water and light damage will appear over time as peeling or discoloring. I would just keep an eye on it.

Answer 3

As far as I know doors don't have a weather rating - they do have a fire rating and sometimes have a rating for insulation.

Since you have a varnish I am assuming you have a wood door. How well it stands up to the weather depends on how well you small porch shelters it, the outer coating, the type of wood, and if it is solid or not.

If it is a solid wood door you would have to really neglect it for it to get torn up by the elements. But that being said - test it out. Spray it with the hose. Does the water soak or run off? If it soaks in a little you might want to add some poly. If not don't worry about it. You can also run hose over porch to see how much water would get to it.

Really this is something that shouldn't be a major concern. It should be part of your bi-yearly house checkup. You should be able to notice water damage way before your door isn't repairable.

And to answer your question a wood door isn't water-proof in the purest sense. You would need to get a fiberglass door for that. I would rather have wood rather than steel which in your situation - taking off screen door - could lead to rust on the bottom of steel door.